I haven't seen a lot of info about this here before, and I had never thought about buying a polymer lower, since forged aluminum lowers have historically been plentiful and cheap.

However, I've noticed that polymer lowers are now available for around $120 - $150, which is considerably less than aluminum lowers are selling for. That's when it occurred to me that polymer frame handguns have been proved to be extremely reliable, so maybe a polymer AR-15 lower is worthy of consideration, at least while aluminum lowers are selling for outrageous prices. And if the prices of aluminum lowers come back down from the stratosphere, you could always buy one and swap it out, and in the meantime you would have had a working rifle.

Do you have experience with a polymer lower? Are they worth buying, at least as a temporary measure?

A friend has the Bushmaster polymer lower. It's got a few miles under its' belt, no issues.
Then again, I have seen several Plum Crazy and a few others that did crack around the front pivot, and the crack is not repairable.

I would be hesitant unless the part was from a major manufacturer, so you will at least have somebody to go back to if there was an issue.

Originally Posted By grendelbane:I have used a Cavalry Arms MKII lower for many years now. It has served as both a 5.56mm, and a .45 ACP. (The beauty of the Cav MKII design is it will accomodate the old grease gun magazine.

Now, I recently turned 57, and I am not as likely to destroy a firearm that I have paid for with my own money as a 19 year old GI will do with an issued service arm.

Still, I think it has proven itself. Others may not fare so well. I do indeed worry about the buffer tube junction, so cleverly strengthened in the MKII design.

I wouldn't recommend it for climbing over barbed wire, like the young tigers do, but if you treat it respectably, it should provide good service. If it doesn't, you aren't out much.

I have a Cav Arms MKI and a MKII that I've had for years. No problems with them at all. I'm thinking about selling the MKI, but probably will hang on to it.

Most are fine as long as used a dedicated 22LR lowers. The problem is they are trying to make polymer, what was originally designed in aluminum, when you design something for one material and then change to material with different properties without changing the design, you will set yourself of up failure. The weapons like the SCAR that are polymer were designed that way, the parts that are polymer have different stresses on them that are within the limits of the polymer material.

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The only reason I bought a Bushmaster carbon 15 (polymer upper and lower) was because my friend sold it to me 2 years ago for $350 . I threw a slidefire stock on that piece and went to town on it. I have ran that cheap piece of shit hotter and dirtier than a lot of people would dare run their prized Colts etc. It hasn't failed me yet. But i am expecting it to , just don't know when it will. It will most likely be catastrophic when it does go.

With that being said I will never pay full price for a polymer AR , I like aluminum too much

What makes Cav-15's the best is they were designed to be made out of polymers by proper injection mold designers and makers. They play to the strengths of the material, not just made to look like an aluminum lower.

They are extremely tough!!! You can still get them from GWACS Armory in OK. I might pick up one of their bright green lowers!

Originally Posted By freeride21a:What makes Cav-15's the best is they were designed to be made out of polymers by proper injection mold designers and makers. They play to the strengths of the material, not just made to look like an aluminum lower.

They are extremely tough!!! You can still get them from GWACS Armory in Ohio. I might pick up one of their bright green lowers!

Ranier has had some, I'm thinking about picking one up for my Birthday Next month.

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Originally Posted By freeride21a:
What makes Cav-15's the best is they were designed to be made out of polymers by proper injection mold designers and makers. They play to the strengths of the material, not just made to look like an aluminum lower.

They are extremely tough!!! You can still get them from GWACS Armory in Ohio. I might pick up one of their bright green lowers!

Ranier has had some, I'm thinking about picking one up for my Birthday Next month.

I bought a FDE one from them earlier this month. I am building a 12.5" SBR out of it.

I also have an older CavArms OD Green one that I am going to build on. It will probably be built into a hunting rifle of some kind. I have had it for about four years.

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